<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <title>提交反馈</title>
  <style>
    html,body{height:100%;margin:0;font-family:"Microsoft YaHei",sans-serif;background:#fafafa}
    .wrapper{height:100%;display:flex;align-items:center;justify-content:center;padding:20px;box-sizing:border-box}
    .box{width:40%;height:40%;min-width:360px;min-height:320px;background:#fff;border-radius:8px;box-shadow:0 8px 20px rgba(0,0,0,.25);padding:40px;box-sizing:border-box;display:flex;flex-direction:column;justify-content:center}
    h1 {
    color: #ff6633;
    margin-bottom: 0px;
    font-size: 24px;
    text-align: center;
}
    label{font-size:14px;margin-top:0px}
    textarea{width:100%;padding:10px;border:1px solid #ccc;border-radius:4px;resize:vertical;font-size:14px}
    input{width:100%;padding:10px;margin-top:4px;border:1px solid #ccc;border-radius:4px;font-size:14px}
    .btn{width:100%;padding:10px;margin-top:20px;background:#ff6633;color:#fff;border:none;border-radius:4px;font-size:15px;cursor:pointer}
    .btn:hover{background:#e55a2b}
  </style>
</head>
<body>
<div class="wrapper">
  <div class="box">
    <h1>提交反馈</h1>
    <label>反馈内容 *</label>
    <textarea id="txt" rows="5" placeholder="请留下您的意见或建议"></textarea>

    <label>联系方式（选填）</label>
    <input id="contact" type="text" placeholder="邮箱或电话" />

    <button class="btn" onclick="submitFeedback()">提交</button>
  </div>
</div>

<script>
function submitFeedback(){
  if(!document.getElementById('txt').value.trim()) return alert('请输入反馈内容');
  alert('感谢您的反馈！');
  location.href = 'index.html';
}
</script>
</body>
</html>